The use of a machine called a ventilator to take over or assist breathing. Arrested or severely impaired breathing may be due to head injury, brain disease, an overdose of opioid drugs, chest injury, respiratory disease, a nerve or muscle disorder, or major chest or abdominal surgery. Ventilation may be needed if a muscle relaxant has been given during an operation as part of general anaesthesia. Premature babies with respiratory distress syndrome may also need ventilation for a period until their lungs develop sufficiently. Positive pressure ventilation (continuous pumping of air under high pressure) may be used in the home in the treatment of sleep apnoea.
(1) Passage of air into and out of the RESPIRATORY SYSTEM.
(2) The process by which air is puri?ed and circulated in domestic, occupational, industrial, and other settings. Ideally, the air we breathe should be of the right temperature and humidity, and free of dust, smoke, pollen, and other contaminants. Ventilation aims to produce such an atmosphere. Air-conditioning is frequently used in hospitals, o?ces, and other
public places. Special ?lters may be used to reduce the risk of airborne infections and allergies (see ALLERGY), but poorly maintained and contaminated systems may result in outbreaks of serious disorders, such as LEGIONNAIRE’S DISEASE. Sterilisation of air is rarely required, but ultraviolet light is sometimes used to kill pathogenic organisms. (See also ASTHMA; BRONCHITIS; HUMIDIFICATION.)
n. 1. the passage of air into and out of the respiratory tract. The air that reaches only as far as the conducting airways cannot take part in gas exchange and is known as dead space ventilation – this may be reduced by performing a *tracheostomy. In the air sacs of the lungs (alveoli) gas exchange is most efficient when matched by adequate blood flow (*perfusion). Ventilation/perfusion imbalance (ventilation of underperfused alveoli or perfusion of underventilated alveoli) is an important cause of *anoxia and *cyanosis. 2. the use of a *ventilator to maintain or support the breathing movements of patients. Invasive ventilation involves the insertion of an endotracheal tube (see intubation), through which air is blown into the lungs; patients need to be paralysed and anaesthetized. This need can be eliminated by using techniques of *noninvasive ventilation.
When we breathe in, the outward movement of the chest increases the volume of the lungs and the pressure in them falls below that of the outside world. Therefore, air is drawn in automatically. When we breathe out, some air exits because of the normal elastic recoil of the lungs, but we also force air out by using the muscles of the chest and the DIAPHRAGM. Replicating this arti?cially involves using a device to produce intermittent positive or negative pressure ventilation as described below.... artificial ventilation of the lungs
The procedure, usually carried out in an operating theatre or intensive-care unit, in which a device called a VENTILATOR takes over a person’s breathing. This is done for someone who is unable to breathe normally. Damage to the respiratory centre of the brain as a result of head injury, disease of the brain, or an overdose of sedative or narcotic drugs may affect the respiratory centre. Chest injuries, disease of the lungs, nerve or muscle disorders or surgery of the chest or abdomen can also affect breathing and require the use of a ventilator to maintain normal breathing. Arti?cial ventilation can also be carried out as an emergency by mouth-to-mouth resuscitation. (See also ANAESTHESIA; ARTIFICIAL VENTILATION OF THE LUNGS.)... ventilation, artificial
(V/Q scanning) a nuclear medicine technique in which two different isotopes are used, one inhaled (usually *xenon-133 or *krypton-81m), to examine lung ventilation, and the other injected into a vein, to examine lung perfusion. In *pulmonary embolism, the area of lung supplied by the blocked artery is not being perfused with blood – which gives a perfusion defect on the film – but has normal ventilation. This technique is highly sensitive for pulmonary embolism.... ventilation-perfusion scanning
Health Encyclopedia